Laser-induced dynamic wetting behavior and interfacial evolution of AlSi5 alloy on Ti6Al4V alloy

Compared with isothermal wetting, laser-induced wetting behavior exhibited a significant contrast within the spreading mechanism owing to the short thermal cycle and migration driven by the thermal gradient. In this study, laser-induced wetting behavior of AlSi5 alloy on Ti6Al4V substrate was investigated. The process was captured by a self-built dynamic data acquisition device and interfacial microstructure evolution was explored. The mechanism for spreading was evaluated by finite element simulation, spreading dynamic and thermodynamic analysis. The wetting process was controlled by reaction product at the early stage and dominated by adsorption of elements at a later stage. The wettability was promoted with increasing irradiation time until 1.4 s. After prolonged irradiation, IMC composed of TiAl₃ phase evolved from granular to rod-shape. Continue to irradiate, multiple Ti-Al phases and Ti₅Si₃ precipitates were produced. At central zone, Al atoms were more likely adsorbed onto Ti substrate, which facilitated the growth of Ti-Al phases. At front zone, the adsorption rate of Si atoms onto Ti substrates was accelerated and the decomposition of Si-rich phase further promoted the spreading. The elucidated relationship between wetting and microstructure could provide a reliable guide for obtaining relatively good wetting without generating over-thick compounds.